SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e9de4168a057dce6d1be519ded80023edc5aba597b2a529d3021de0d3d0fc0f5' 
  AND token = '4x6OSk4t+S7pMfJgmHgBvzLUINYMOydc2nDG5ZRMcSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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