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SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '74f5a72fbe02499b4d282637abb0fc4fda75620cdfe1a80a4b378fd7a077cafb' 
  AND token = 'Pygr3CbNB3dpzkDfO3iybPn8mkxI4x1LdECKD2d6n2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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