SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4e339d3c0f404fb277987cbcb2d2b18bea3931cad0ecabed2c1d2a21699c9bb' 
  AND token = 'ZruXb2rXADsMJABHWw5ZyQmyrnz24aO/NQ8puMEppdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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