SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9556e8beecd67c690c5ae2b76e63222d0c6f86a848e571da833081dd8a45f9e5' 
  AND token = '/Jp3RPktRiSBmvKQhddaiahX6jBeYBASnMb2qzKUG3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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