SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7075c585c0ad45069cfe531848eb341544d7e03d8d5da6bb809dee21bf90265' 
  AND token = 'ELB9a5o/g+XYTt+XLYns5vEtqTYlZpciDisLRcSqJ7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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