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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd21c1b7c1acb266ada6daf9a3d3e4688a94b52cfe0070aadcfbd5f6666c17cfb' 
  AND token = 'YCRXnhGQoQuhzG4NKyl7L3RvT+aiWIqj2Jzx6yffCBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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