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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5250495acb1c8e3508be6a3a63963d592a97d38c1005002757ba624f7cbd6563' 
  AND token = 'uvant3fNvnqJi8fGhJrDRSlTo8pMfGDulK70o/JXjaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}