SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1500ed889c29e70d823402e9e00fdc570927a62941513527562df1a909d96fa3' 
  AND token = 'Ju40wWlJm1FyyYi4cs/7vFywPNxtVoTbR2XTEOLfsyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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