SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2c96080ab5e4377e12db53f114d37c51607bc55b85c0516b66485c90d9e6d30' 
  AND token = 'mSDBhsI/JQZSUSUFAlCStb5jB+rVYtqgDNDfhvkbzeo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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