SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03bf19814708d34fd5963bae15867978bed711d7934336f578c5c7f30076f6aa' 
  AND token = '7M3W34YU30FxC+ad/2FbHgcniKO5fvJFFjlRq4eKiLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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