SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bdf2f4d0f11125eb20ccd8ae89fade5aad60db71140daca862b81691e49152a' 
  AND token = 'LgMNU+Uy8iSMkXIa50g3yldscClsflwroWgVGMaJxUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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