SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '939f6e1e7e0c8364972e9e39e29857a2180250fe38bd02ac36cff3de9501b6b0' 
  AND token = 'FoTtcwJdr2Pp1mi+zbMm1p5A00sreRWXRQ/aaMfLTgc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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