SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4afdd57c3ad13c11b001cb508411ee0bf3afc22144c9f31f460e447f6dee0b8e' 
  AND token = 'D/sSTJ80p9NQSlx9vaMqwBEpefv5dfDuusnLK2H+bj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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