SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56dd510752618f2c6aaa6cf275c3387eced3ac730fe0b7bf0589fa2a4386ad1f' 
  AND token = 'gnkt3lEIm4vWt+9nqVb1jj3HPupBr1blfHKlIZ6FmBY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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