SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5234940cd19ff21a9ac2a3a48f14f2956113dc15e2c8b605b98435560bad351' 
  AND token = 'Pz+1Y2c/f+ThL8rzU7iRXiP2ZTtLrqYPXwJXlEquSYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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