SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9fc8a4ae928f5beb73420f3f14f2d3791d5f160703064285396907d3209f331' 
  AND token = '/9nlVqO1/LnvgFFSNW9hO9nqQ/CvKG4vSKAtf7Tqj5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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