SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91f8ddcc890c5d91e99134a898c7102144fa3f4f3684d1b2ea83cede66eb8d4f' 
  AND token = 'M7KUhtbEoVWKeND9uWTApxEjubo1kR2z3E8M3jl65VQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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