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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81406bddfa6d2829c13fd4b2d31cfd59f2b3eb9cb0d7cb45f790c7a81b70c34e' 
  AND token = 'LU0W7N3w6eWL/7zHBMDobJ1xbgQJTuErXzte9IiuppI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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