SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c5e7f55f16db2b843f94bd1acbb5922225d048e2c3d27009cc9ac97663f06bb' 
  AND token = 'rtiBmkQvEydjrVi3nWF7O2SdjPEbsMfKXh8F9B/mhc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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