SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c98ceddcb8c06a39a7c43472c0e08f570e98f777442a39abd042c90d0712691' 
  AND token = 'qPhMGmK2u1QKL1CtQMzaZBuGLQHrofs8VJjXqY7AlKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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