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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6fb98dbbc41b0ac823a02e2a7cac4e0781abf5c0cb8e4ce29a6ee2549fe4176e' 
  AND token = 'TXL0C56XNrb+0uj7rDPRNWyHrkEVvfeGHfAxpI65rY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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