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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c4b1b54d00c7ae0c31d3d9b5274b4553cb43ef10ce2c44d673b1005c3e5d8481' 
  AND token = 'Ghch69CHyHeyUoaBDDd3yfkgbkfqV905IFGlNPSSfRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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