SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '287dc3c67abb819b0d1022d3a8c681ac87b0f0df85b57c801b674d20132acd35' 
  AND token = 'WuPkORg4Bi14gD+uT8MMMW6DSO8ck6afkRByKYibpdo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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