SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b52265658c7207a8165d1b4c31a1daedcf38876d8bd8b62f950d121b2b3a0c8b' 
  AND token = 'kQesTH+nqaBOfwbtXDp3YvPcUlsKjz0NTAGkqB8QjN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}