SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10a6c2be19b374016e8c537fd565b9465dc3b02f2531d7f1f8aa934023eb75cd' 
  AND token = 'vKHKw8XmuONni8obDwvtlgDRSfCQFvbTZCj3195KYwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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