SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b14f2b57d5c52a14d3d3fcb0350c92178d03beec97cd90c2e367d6d82cdb8f0' 
  AND token = 'GnAijDiw6hmYyZ4/GdwI+IEhZ/CxRY7EtvM3QBA2wo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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