SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9df8eb727ff2bc6fe5db4359bcfe03999b47b277eec4dc18be4a335eb9a0563' 
  AND token = 'igS2Noo08hFMq8EjPy+qPgAW9fC2T7CNUp1RPFgrPlI=' 
  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"
    }
  }
}