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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '981af905ab671226aabb54993cf85821223e4bb38573602580609292b0e6ac50' 
  AND token = 'dySY1w0nCONdJGNKtFHEHzEgHcQSB2y5DLgoS9aATHw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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