SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccfa50d1019b4dd5b31864d7c0979e7a80a37b6de2c04091d67d9306e6b0fe0d' 
  AND token = 'mwZO0ZZR6drWEYofB+s0IzZRfarPXj+FMbiX0uhfHTY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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