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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b48a1db22b8dba87fa3bf83e454a5d5013361f60cfae53afd0bf2a3c4f6d80ba' 
  AND token = 'cu58qV9CE26U0kmO9kyWWBmfWyH6IHD4obZajMTb7Bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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