SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59c76f492418ee375ffdadd71ea3bb65206799f5250c9021e1c90233ab2408a2' 
  AND token = 'RNdwFiQAOIhWDGlmJZbo13poGHdalBTFR3VOtKJ4/Bw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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