SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48f96d1c2088e03a7e206b158c1467dae43da9a4f1863897dac3183fb6e03c59' 
  AND token = 'tkysv6fRotcZfSiBT5LuLWClfqpuoo/qLKuKLREtdL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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