SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8fdcf7477a52fcf470d74f615a7752ce69780a372243ba4c7417f128145c05b' 
  AND token = 'JTYBsXx5soEypjNBjvnLdOJDuJtVCzG/w075WoWODn8=' 
  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"
    }
  }
}