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SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'c36aef0e73cddd8109ef856ef97a984a7101773c5eb83c2e4b352c8fa8311405' 
  AND token = 'qbliMDRMskh7RLxcSmHKDGvif44XoN5S8daU4uRR92U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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