SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98a9208d0b0e44ed0affe9604c3cc3d9ccd7b49ac8639d1a151df95bd6434227' 
  AND token = 'DbTCTBsI2JbSGJBLT4vMfWQ/It4XUE4hheiIvPEluVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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