SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42eca75f5448cd8ec7113be9846d3e6cf03b6585ccba020f78b8e6b5a909ac5a' 
  AND token = '/G1YS4BQ05wz2iYNCX0A7cwN/M+lnR0+iAuUFniVR0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}