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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a436a0d31dd146856cde7b3c01ee6b8ce0045bc77eb2ba5fd2c9cf3094e0ec66' 
  AND token = 'FHPjX21eKNQIYy2NMPrWRzb5CodsEhey3Al9DsKi0Vk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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