SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a17c219abc4e7d7c0bfbe0f10b8ee5b701835ecbe77c04dde953e7f1aef40d1b' 
  AND token = 'F2/VBsHIRCPgp8cUu4Aq4MV3EEibxBEZVVOwKGuLPt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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