SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '525ee53a6e5364c999a8dada5eef9fa9e02c42c9f0f0ed968d796f384c86abd4' 
  AND token = 'OkEYKmNfAZVPRY07bR8zBUCR5cXrSQ7EDLHS2UgqCt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}