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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f6fe8b3b2013ddd6c2ea0c000bc6ed389cd8eaeb8372cff82f90eda1fb3ecd1b' 
  AND token = '76fcBSUHlrgDZLDR0q3VQNWPf82i3kR0W6eYjYYB3M0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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