SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d9fa42fdb49f906887064018870a611a3ccc8f210f5bd324a7e516d8e1e393a' 
  AND token = 'ghol1zzuTtuB8CVMKQTEPWFZbJyV7+xBswVq4644jjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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