SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '803a21faf944ee485e17897fb224a279c2a2e90c0cc26ec194bb629c36dbcf48' 
  AND token = 'gvecGPZDf2MjeNHzEeRsls/LX6P6Hy7w6cG85hK/oRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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