SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c43ad46e6784db8f1063821f3ac2c8176300a0906be29f09519b98812448937' 
  AND token = 'WH5YH5nQ7KuSZuuZaZVv9lCuZJD4/Lm6UbCGFFWO+8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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