SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58ada562868abf3b35fcbf755c269dea4215f33d4688170f7ca4901de5cec114' 
  AND token = 'LNbvSnBnXMRLKbQ4LVy8tvFBvCSxettQVSIEOvWKbL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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