SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0f7c65deacfbfd3f79a3ada47be1e680b891f5568454a0fcc5403b517ca2102' 
  AND token = 'nGbJyYXQTr3iku657JkMcucG26u22BbulnS6I+gWMp4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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