SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e523a7fbc58aee9ce05eb28578e0aecf70b32b9e0dafbca062bc5398d6c007ac' 
  AND token = '3IfBcHnF+Fz54cnzH2Q4j9vLexqEmqnjLr4K7yvcsQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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