SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e34c626e615a6bd94b6977b34c75d86bcd9520b704203750afe0ad12e3def313' 
  AND token = 'dOFoY+0z9BAJJvfy+9xOATZe8YUFXHOSrita5AqadIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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