SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5050649a8f86c758a58b6e78d9c11559423e0df7f638ad9c4523f4cfa248384' 
  AND token = 'LvrGWzNsdYr2yG4XH4UBsBNDrmjUL58PmSwYZ+Zbhr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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