SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c76e694612b46228f1a82fbdeb512b7772ad3131dd0b509e594aa8873d8bf52c' 
  AND token = 'YhWz4RBji54VE1jnI3mmqZtTpqu3e1DAX7Q7GFnCwoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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