SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57f0cc14fe63e0648ed9556049985b1572330eb86e1b5cc377a1df90465bc5ea' 
  AND token = 'Bl4F+rSy0WfY5yYNJaUeYL2rxeBguHhOpBuXlyRIA4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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