SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '398c21fd8fb59045e3b67617699bebd6d19acbb44839cb941dd7d1581f0a8374' 
  AND token = 'FwBeBuXiZVei/NsTZWne4jPoDomDAkuGZvy/qbq+Chs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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