SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7799b357aaab565403244e6f175b3e0cd8913e596a29ac0ecf5368e8050cf0b0' 
  AND token = '79JbyhkMcXr1dr7udFz5s6+J2fPBVZSqXL2eAJXm+9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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