SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c81cc87c3fc1886efe8fb2fefff26e50a524d2f267b03c8d749d947ce786029' 
  AND token = 'kHrKMAWaC0Tm19xqh1+CwsU85gvsdbWdAgRzaEEdphY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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