SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73ae886b3039ef4f39df53474c972f4f7f8607b8ab9d805cc2e5e95332cd2687' 
  AND token = 'VDL16AdUu1yI10T9e6iwyWXEYvmScmPGQbDgKEffUh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}