SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0c49a0971d951b14eb3ee44b7f90d034af2917267f13183ddf3887d8ad76438' 
  AND token = 'IMSxchfQFNIzofggXloZ8FpdFPZbXmSW1sAJqUOPGoU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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