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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e1a6bd762f480245a441d0f4fc9b823644d50a439d7696dfaf9ec91a95e0939e' 
  AND token = 'n7s2rGwcYLle0EbktT22hNL31QkJC6sn/7Y+k7/cQV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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