SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f2c119e589b280c17e620f88585c3cfc7dc1c353d1875549c383975556cedab' 
  AND token = 'PqGcNyz0vYaKbb3YHAkku0Dv3X2iGyGCJRCqlKoHHVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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