SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d5f90468cb33343d0278e139ee190bc28e50b349364987f0661d852a38575c9' 
  AND token = 'uQD0fJ8PJWHCK64Ey+5Y/29bYuD38uWsDAlDFXInIw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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