SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5928df4b87c08a8a73da8360afd47524fab1bdc610042f5f09652a09c91d2cab' 
  AND token = 'd3pymoDtwKepF74CUKguftBkDJYl73z5MbaZ04bmhyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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