SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '293103e35290fd983167259990b712802aac16b139cc0b88b70c2eccb044c912' 
  AND token = 'MWAj6xv4zJDVDSzWYJmk1ESwQhsEYWSE5TIbvHnHg4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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