SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a488beac54999cf13e4c82fe483e7e47f8f7caeb2bcf5412b5266be35e7fc1c' 
  AND token = '/dVZKCpEqEcftNNtqUWl75t5UU64XRQJYtR6j+dmquM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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