SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1d80762b903f02919d7aeddbbd528d2748b17268661e724b597557c4d972a8c' 
  AND token = 'oinrsApajpDuNlVN34mk2rIk5wQ2dtUDRP46mqV8FRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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