SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b69f14558a12be89e27734571424e1e937fad6cf77e0977ddbbdc4f66c7cf74' 
  AND token = 'th2pz+npuVRxqmvdsHrhqBvfyqzOeHO+B/RNdChBaoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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