SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29f5f365c1c8e951e81996a37ec62a886b0a0586fe79fb7a63d6d854ad412482' 
  AND token = 'CZdyTdFZHyLgBGuivbb5xdJGS7+om2HaGLZ63jwvvkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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