SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81c134d6ff14d8a09ceb554d2b455475a02564a3e255fafe99d945fb9fd3caf5' 
  AND token = 'WGMjNltJbgirYInKjQHsWmOruV/xpMx/KUVjoS0b3Hg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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